Monitoring system for monitoring a hybrid power plant of a rotorcraft, associated rotorcraft and method

Abstract

A monitoring system for monitoring a hybrid power plant of a rotorcraft comprising at least one rotor. The hybrid power plant has an electric motor comprising a first drive shaft, a heat engine comprising a second drive shaft and a gearbox. The monitoring system includes at least one first sensing device measuring a first item of torque information representative of a first engine torque C 1 transmitted by the first drive shaft to a first input shaft of the gearbox and a controller comparing the first engine torque C 1 with a first limit value VL 1.

What is claimed is: 
     
         1 . A monitoring system for monitoring a hybrid power plant of a rotorcraft comprising at least one rotor, the hybrid power plant comprising:
 an electric motor electrically connected by an electrical connection to at least one electrical energy source, the electric motor comprising a first drive shaft;   a heat engine comprising a second drive shaft; and   a gearbox comprising:   a first input shaft connected by a first mechanical connection to the first drive shaft;   a second input shaft connected by a second mechanical connection to the second drive shaft; and   an output shaft connected by a third mechanical connection to the at least one rotor,   the monitoring system comprising:   at least one first sensing device measuring a first item of torque information representative of a first engine torque C 1  transmitted by the first drive shaft to the first input shaft; and   a memory storing a first limit value VL 1  relating to the first engine torque C 1 ,   wherein the monitoring system comprises a controller and a first reversible transmission device, the controller comparing the first engine torque C 1  with the first limit value VL 1  and consequently controlling the first reversible transmission device transmitting the first engine torque C 1  and, alternatively preventing the transmission of the first engine torque C 1 , the first reversible transmission device being controlled to allow the first drive shaft to rotate the first input shaft when the first engine torque C 1  is less than the first limit value VL 1  and to prevent the first drive shaft from rotating the first input shaft when the first engine torque C 1  is greater than or equal to the first limit value VL 1 .   
     
     
         2 . The system according to  claim 1 ,
 wherein the first reversible transmission device comprises a first clutch positioned in the first mechanical connection, the first clutch being arranged in an engaged state when the first torque C 1  is less than the first limit value VL 1  and the first clutch being arranged in a disengaged state when the first torque C 1  is greater than or equal to the first limit value VL 1 .   
     
     
         3 . The system according to  claim 1 ,
 wherein the first reversible transmission device comprises an electric switch positioned in the electrical connection, the electric switch being arranged in a closed state when the first torque C 1  is less than the first limit value VL 1  and the electric switch being arranged in an open state when the first torque C 1  is greater than or equal to the first limit value VL 1 .   
     
     
         4 . The system according to  claim 3 ,
 wherein the electrical connection comprises an inverter transforming a direct electric current of electricity stored in the at least one electrical energy source into an alternating electric current supplying electricity to the electric motor, the electric switch being positioned along a direction of flow of the electric current between the at least one electrical energy source and the inverter.   
     
     
         5 . The system according to  claim 3 ,
 wherein the electrical connection comprises an inverter transforming a direct electric current of electricity stored in the at least one electrical energy source into an alternating electric current supplying electricity to the electric motor, the electric switch being positioned along a direction of flow of the electric current between the inverter and at least one terminal supplying electricity to the electric motor.   
     
     
         6 . The system according to  claim 1 ,
 wherein the at least one first sensing device comprises a voltage sensor measuring an electrical supply voltage between two terminals supplying electricity to the electric motor and an intensity sensor measuring an electrical intensity of an electric supply current flowing in the electrical connection.   
     
     
         7 . The system according to  claim 1 ,
 wherein the at least one first sensing device comprises a rotational speed sensor measuring a rotational speed of the first drive shaft in relation to a housing of the electric motor.   
     
     
         8 . The system according to  claim 1 ,
 wherein the monitoring system comprises:   at least one second sensing device measuring a second item of torque information representative of a second engine torque C 2  transmitted by the second drive shaft to the second input shaft;   the memory storing a second limit value VL 2  relating to the second engine torque C 2 ; and   the controller comparing the second engine torque C 2  with the second limit value VL 2  and controlling a second reversible transmission device configured to transmit and, alternatively, prevent the transmission of the second engine torque C 2 , the second reversible transmission device being controlled to allow the second drive shaft to rotate the second input shaft when the second engine torque C 2  is less than the second limit value VL 2  and to prevent the second drive shaft from rotating the second input shaft when the second engine torque C 2  is greater than or equal to the second limit value VL 2 .   
     
     
         9 . The system according to  claim 8 ,
 wherein the second reversible transmission device comprises a second clutch positioned in the second mechanical connection, the second clutch being arranged in an engaged state when the second engine torque C 2  is less than the second limit value VL 2  and the clutch being arranged in a disengaged state when the second torque C 2  is greater than or equal to the second limit value VL 2 .   
     
     
         10 . The system according to  claim 8 ,
 wherein the second reversible transmission device comprises a fuel metering valve supplying fuel to the heat engine, the fuel metering valve being arranged in an open state with a non-zero fuel flow rate when the second engine torque C 2  is less than the second limit value VL 2  and the fuel metering valve being arranged in a closed state with no fuel flow when the second engine torque C 2  is equal to or greater than the second limit value VL 2 .   
     
     
         11 . The system according to  claim 8 ,
 wherein the second reversible transmission device comprises a cut-off valve supplying fuel to a fuel metering valve, the cut-off valve being arranged in an open position with a non-zero fuel flow rate when the second engine torque C 2  is less than the second limit value VL 2  and the cut-off valve being arranged in a closed position to cut off the flow of fuel when the second engine torque C 2  is equal to or greater than the second limit value VL 2 .   
     
     
         12 . The system according to  claim 8 ,
 wherein the at least one second sensing device comprises a torquemeter directly measuring the second engine torque C 2 .   
     
     
         13 . The system according to  claim 8 ,
 wherein the monitoring system comprises:   at least one third sensing device measuring a third item of torque information representative of a third engine torque C 3  transmitted by the output shaft to the at least one rotor;   the memory storing a third limit value VL 3  relating to the third engine torque C 3 ; and   the controller comparing the third engine torque C 3  with the third limit value VL 3  and controlling at least one reversible transmission device from among the first and second reversible transmission devices, the at least one reversible transmission device being controlled to allow the first and second drive shafts to rotate the first and second input shafts when the third engine torque C 3  is less than the third limit value VL 3  and to prevent at least one of the first and second drive shafts from rotating the first or the second input shaft respectively when the third engine torque C 3  is greater than or equal to the third limit value VL 3 .   
     
     
         14 . The system according to  claim 13 ,
 wherein, when the third engine torque C 3  is greater than or equal to the third limit value VL 3 , the controller firstly controls the first reversible transmission device to prevent the first drive shaft from rotating the first input shaft, then the controller controls the second reversible transmission device to prevent the second drive shaft from rotating the second input shaft.   
     
     
         15 . The system according to  claim 13 ,
 wherein, when the third engine torque C 3  is greater than or equal to the third limit value VL 3 , the controller simultaneously controls the first reversible transmission device to prevent the first drive shaft from rotating the first input shaft and the second reversible transmission device to prevent the second drive shaft from rotating the second input shaft.   
     
     
         16 . A rotorcraft comprising a hybrid power plant and at least one rotor, the hybrid power plant comprising:
 an electric motor electrically connected by an electrical connection to at least one electrical energy source, the electric motor comprising a first drive shaft;   a heat engine comprising a second drive shaft; and   a gearbox comprising:   a first input shaft connected by a first mechanical connection to the first drive shaft;   a second input shaft connected by a second mechanical connection to the second drive shaft; and   an output shaft connected by a third mechanical connection to the at least one rotor,   wherein the rotorcraft comprises the monitoring system for monitoring the hybrid power plant according to  claim 1 .   
     
     
         17 . A monitoring method for monitoring a hybrid power plant of a rotorcraft comprising at least one rotor, the hybrid power plant comprising:
 an electric motor electrically connected by an electrical connection to at least one electrical energy source, the electric motor comprising a first drive shaft;   a heat engine comprising a second drive shaft; and   a gearbox comprising:   a first input shaft connected by a first mechanical connection to the first drive shaft;   a second input shaft connected by a second mechanical connection to the second drive shaft; and   an output shaft connected by a third mechanical connection to the at least one rotor,   the monitoring method comprising at least the following steps:   measuring, with at least one first sensing device, a first item of torque information representative of a first engine torque C 1  transmitted by the first drive shaft to the first input shaft; and   comparing, with a controller, the first engine torque C 1  and a first limit value VL 1 ,   wherein the monitoring method comprises controlling, with the controller, a first reversible transmission device configured to transmit and, alternatively, prevent the transmission of the first engine torque C 1 , the first reversible transmission device being controlled to allow the first drive shaft to rotate the first input shaft when the first engine torque C 1  is less than the first limit value VL 1  and to prevent the first drive shaft from rotating the first input shaft when the first engine torque VL 1  is greater than or equal to the first limit value VL 1 .   
     
     
         18 . A monitoring system for monitoring a hybrid power plant of a rotorcraft comprising a rotor, the hybrid power plant comprising:
 an electric motor electrically connected by an electrical connection to an electrical energy source, the electric motor comprising a first drive shaft;   a heat engine comprising a second drive shaft; and   a gearbox comprising:   a first input shaft connected by a first mechanical connection to the first drive shaft;   a second input shaft connected by a second mechanical connection to the second drive shaft; and   an output shaft connected by a third mechanical connection to the rotor,   the monitoring system comprising:   a first sensing device capable of measuring a first item of torque information representative of a first engine torque transmitted by the first drive shaft to the first input shaft; and   a memory storing a first limit value relating to the first engine torque,   wherein the monitoring system comprises a controller and a first reversible transmission device, the controller capable of comparing the first engine torque with the first limit value and consequently controlling the first reversible transmission device transmitting the first engine torque and, alternatively, preventing the transmission of the first engine torque, the first reversible transmission device controllable to allow the first drive shaft to rotate the first input shaft when the first engine torque is less than the first limit value and to prevent the first drive shaft from rotating the first input shaft when the first engine torque is greater than or equal to the first limit value.   
     
     
         19 . The system according to  claim 18 ,
 wherein the first reversible transmission device comprises a first clutch positioned in the first mechanical connection, the first clutch being arranged in a physically engaged state when the first torque is less than the first limit value and the first clutch being arranged in a physically disengaged state when the first torque is greater than or equal to the first limit value.   
     
     
         20 . The system according to  claim 18 ,
 wherein the first reversible transmission device comprises an electric switch positioned in the electrical connection, the electric switch being arranged in a closed state when the first torque is less than the first limit value and the electric switch being arranged in an open state when the first torque is greater than or equal to the first limit value.